Steam-engine



2 SheetS- Sheet 1'.

B. JACKSON.

(No Model.)

STEAM ENGINE.

Patented Jan. 2, 1894.

' &

Fig.1. J,

a: Atmosph e re nnnnnnnnnnnnn HoaiuPmua com'mr.

(No Modelzi) 2 Sheets-Sheet 2/ B. JACKSON. STEAM ENGINE.

No. 511,954. I Patented Jan. 2, 18-94.

-n Ztnesses: 1250622602": i

U ITED STATES PATENT OFFICE.

BYRON JACKSON, OF SAN FRANCISCO, CALIFORNIA.

STEAM-ENGINE.

SPECIFICATION forming part of Letters Patent No. 511,954, dated January2, 1894.

Application filed April 13, 1893- Serial No. 470,197 (No model.)

To all whom, it may concern.-

Be it known that I, BYRON JACKSON, a citizen of the United States, and aresident of the city and county of San Francisco, State of California,have invented certain new and useful Improvements in Double-ActingCross-Oompound Steam-Engines; and I hereby declare the followingspecification and the drawings therewith to be a full, clear, and exactdescription of my invention and the manner of constructing and operatingthe same.

Myinvent-ion relates to that class of doubleactingsteam engines called.cross compound, where the steam pressure is applied successively on twopistons and in two cylinders, passing from one to the other, the pistonsmoving in opposite directions, and connected to cranks set one hundredand eighty degrees apart or opposite, and especially to the valve andvalve chamber and ports of such engine.

My invention consists in arranging such engines as close together aspracticable, and in the intersecting curves of the cylinders placing apiston valve of peculiar construction as near to, or as near in theplane, of the cylinders as is most convenient, and in so const ructingthe piston valves that the central piston thereof will perform thefunction of admission for both ends of the high-pressure cylinder, andso the two end sections thereof will perform the release of steam fromthe high-pressure cylinder, and both admission and release for thelow-pressure cylinder.

The object of my invention is to simplify the construction of suchengine, and also to secure a more perfect steam distribution to bothcylinders, and to dispense with a steam pipe or receiver between them bya single valve, as shown in the accompanying drawings, in which Figure 1is a central section through thev cylinders and valve of a compound,doubleacting steam engine constructed according to my invention, takenon the line 00m 00 of Fig. 2. Fig. 2 is a transverse section on the liney y of Fig. 1, with the valve removed, and showing the relative positionof the two cylinders and single piston valve for steam distribution.Fig. 3 is a steam indicator diagram illustrating the degree of pressurein the two cylinders throughout one complete revolution, and the natureof the steam distribution attained by my improved multiple piston valve.Fig. 4: is a diagram to illustrate the method of the valves operationmore clearly than is possiblein the shaded figures of the drawings.

Similar letters of reference are employed to designate like parts in thedifferent figures 0f the drawings.

Referring first to Figs. 1 and 2, I .preferably form the two steamcylinders A and B with the valve chamber 0, and the baseplate D, all inone casting, the valve E being placed as near to the cylinders A and Bas practicable; yet the two cylinders and valve chamber might be inseparate castings if desired. The high-pressure piston F, and thelow-pressure piston G, being connected by the piston rods I andJ tocranks set opposite, or one hundred and eighty degrees apart, thepistons assume the position shown in Fig. 1, at the extreme of onestroke. The piston valve E is connected by the rod K to an eccentric onthe engine shaft, and is adjusted by a centrifugal governor to cut offsteam admission to both cylinders at various points of the stroke as thespeed and power required may demand. Steam enters at the nozzle L and isdischarged at M. Its course through the steam cylinders can best beexplained by reference to the diagram, Fig. 4, where the valve E isshown in corresponding relation to the position of the pistons F and GinFig. l, or at the beginning of one stroke. The central chamber N is inconnection with the inlet nozzle L, and is constantly filled with steamat boiler pressure.

0 and O are passages leading to the ends of the high-pressure cylinderA, and P and l? are ports leading to the ends of the lowpressurecylinder B. All these passages or ports extend around the valve bushingQ, as shown at ain Fig. 2.

For the purpose of convenience in construction, and accuracy of fittingthe valve and ports, I insert in the valve chamber a bushing, throughthe sides of which are ports, as shown, accurately spaced to correspondwith the steam ports in the cylinder, and in accordance withv theworking edges of the valve. Across these ports are diagonal bars, sothat the packing rings in the valve will pass over the ports withoutobstruction or danger of catching. These diagonal bars cause the Wear tobe uniform on the valves and packing rings.

Referring now to the course of steam: When the pistons A and B and thevalve E are in the position shown in Figs. 1 and 4:, steam from thechamber N passes through the ports S and 0' into the front end of thehigh-pressure cylinderA to begin the stroke. At the same time the port 0leading from the back end of the high-pressure cylinderA is open andsteam passes from this port, as indicated by arrows, into the port Pinto the back end of the low-pressure cylinder 13; at the same time theport P of the front end of the low-pressure cylinder B is practicallywide open, permitting the Waste steam from that port to escape into thechamber T, and through the interior of the valve E to the exhaust outletM. This lead or early opening of the exhaust port P being at the pointof fastest travel of the valve, causes a free exhaust. The valve E moveson to complete its stroke, fully opening the ports S and P as will beunderstood. The exhaust steam from the port P, and from the low-pressurecylinder B, fiows into the chamber T, and through the interior of thevalveE to the chamber V, and from there out at M to the open air, or toa condenser, commonly the latter, as is indicated in the pressurediagram, Fig. 3. At the opposite strokes of the engine all theseoperations are reversed in like relation, as will be understood; theexhaust steam from the port P passing directly out through the chamber Tand discharge-way M.

By examining the diagram of the pressure in the two cylinders A and B,as indicated in Fig. 3, it will be seen that the back-pressure line ofthe high-pressure diagram is an expansion line, and corresponds with thelowpressure diagram until the cut-off takes place (which is coincidentin the two cylinders), when the curve in the expansion line changes tocorrespond to the reduced volume of steam in the low-pressure cylinder,and the backpressure line of the high-pressure diagram changes to acompression 'line, the curve of which corresponds to the volume of steamtrapped into the clearance space of the highpressure cylinder and ports.'There being no pipes or receivers between the two cylinders, theexpansion commences at the cut-off in the high-pressure cylinder, andcontinues Without interruption until its release from the lowpressurecylinder, doing work all the time, except the slight drop caused by theclearance between the valve and the low-pressure cylinder, as isindicated by the diagram, Fig. 3, which is taken from actual performanceof engines :made according to my invention. It will be observed thatthereis a single inlet port S opening into the bushing Q, and that theinitial steam passes, first on one side and then on the other side ofthe middle piston X of the valve E, and that the two end pistons X and Xof the valve E perform the functions of release for the high-pressurecyl-= inder A, and both admission and release for the low-pressu recylinder B, and that the ports 0 and O are not covered at any tune byeither piston of the valve E. The space between the middle and endpistons of the valve E forms a portion of the clearancespace of thehigh-pressure cylinder, and notwithstanding the steam pressure isvariable, and not the samein both ends of the cylinder, yet the valve isalways in perfect balance.

It will be seen that all the parts, includlng the cylinders, valve andvalve chamber, are symmetrical in construction each way from theircenter longitudinally, and that the valve E can be inserted from eitherend, and that either end of the valve chamber can become an exhaust wayas the convenience of erection may demand.

Having thus explained the nature and objects of my invention, also themanner of constructing and operating the same, what I claim as new, anddesire to secure by Letters Patent, is

1. In a double-acting,cross-compound steam engine, as herein described,a multiple piston valve composed of three pistons, the center pistonacting, as an admission valve for both ends of the first or initialcylinder, covering or uncovering alternately to the back and front end,a single inlet for steam, and the two end pistons of the valveperforming the functions of release for the initial or first cylder, andboth admission and release for the second orlow-pressure cylinder,substantially in the manner and for the purposes described.

2. In a double-acting, cross-compound steam engine, having athree-piston valve 1n one piece, connected to one valve-stem; a singlevalve chamber with five ports, one of which ports is covered by thecenter piston, and uncovered alternately, admitting live steam from theboiler to the front and back of the initial or high-pressure cylinderthrough the ports connecting the valve chamber with the initial cylinder(these ports never being covered by any of the three pistons), and theports leading to the low-pressure or second cylinder being covered anduncovered by the two end pistons, and alternately releasing the steamfrom the initial cylinder into the second cylinder, and from the secondcylinder to the atmosphere or to the condenser, substantially in themanner and for the purposes described.

3. In a double-acting, cross-compound steam engine, the singlethree-piston valve made 1n one piece, performing the admission andrelease of steam for both cylinders, and made hollowso as to pass theexhaust steam from either end of the cylinder to the other so that itcan be conducted away from the engine at either end of the valvechamber, requir ng no other steam passages or outlets made 1n thecylinder or valve chest casting than the one made to contain the singlevalve; a single valve chamber with five ports, having diagonal barsacross the ports to prevent the packing rings from catching or wearingunequal,

made substantially in the manner and for the purposes described.

4. In a double-acting, compound steam engine having one valve havingthree pistons; a valve chamber with five ports, as herein described; acentral port covered by a central piston of the valve, openedalternately right and left thereby admitting steam to the ends of thehigh-pressure cylinder the low-pressure cylinders and the portsleadingthereto; ports 0 and 0 leading from the valve chamber to the ends of thehigh-pressure cylinder, so arranged as to be not covered by the valve inany position of its stroke, in the manner substantially as described.

5. In a double-acting, compound engine, as herein described, high andlow-pressure cylinders combined, and steam admitted and released in bothcylinders by a single valve,

which is composed of three pistons, the center of which acts as anadmission valve for both ends of the first cylinder, while the two endones perform the functions of release for the first cylinder and bothadmission and release for the second cylinder the valve chamber placedparallel to the cylinders, and symmetrical each way from itslongitudinal center so the valve can be inserted from either end of thevalve chamber, and either end of the latter become a discharge wayforexhaust steam, in the manner substantially and for the purposesdescribed.

In testimony whereof I havehereunto affixed my signature in the presenceof two witnesses.

BYRON JACKSON. Witnesses:

JAMES MASON, WILSON D. BENT, Jr.

